* DNS rebinding protection for the dashboard
Fixes#3083 and replacement for #3629
This adds a new parameter to the `linkerd-web` container `enforcedHost`
that establishes the regexp that the Host header must enforce, otherwise
it returns an error.
This parameter will be hard-coded for now, in `linkerd-web`'s deployment
yaml.
Note this also protects the dashboard because that's proxied from
`linkerd-web`.
Also note this means the usage of `linkerd dashboard --address` will
require the user to change that parameter in the deployment yaml (or
have Kustomize do it).
How to test:
- Run `linkerd dashboard`
- Go to http://rebind.it:8080/manager.html and change the target port to
50750
- Click on “Start Attack” and wait for a minute.
- The response from the dashboard will be returned, showing an 'Invalid
Host header' message returned by the dashboard. If the attack would have
succeeded then the dashboard's html would be shown instead.
Signed-off-by: Alejandro Pedraza <alejandro@buoyant.io>
bd8d47226d